In the past, a wellbore has been drilled and cased to a certain depth. Thereafter, liners are installed and the assembly is cemented. Thereafter, perforating guns are lowered from the surface to perforate at the desired intervals. Each time the perforating gun is shot, it must be retrieved to the surface, reloaded, and lowered again to the desired depth for additional perforation. Multiple trips in and out of the wellbore with the perforating gun cause delays which translate into operating costs for the well owner. Additionally, handling of perforating guns at the surface has its inherent hazards. To answer these needs, the apparatus and method of the present invention have been developed. It features a liner which includes a sliding sleeve. A plurality of ports can be covered or uncovered by the sliding sleeve. The shaped charges are mounted externally to the liner and the entire assembly is lowered into the wellbore to the desired depth. Multiple sections can be used so that the perforation occurs at the desired depth or depths. Once the entire assembly is installed, the charges are set off from the surface at the desired depths. A packer may then be set and a production string installed for production from the formation. Alternatively, a packer can be run and the well completed before setting of the charges.